Elevator installations are usually arranged in an elevator shaft connecting a number of floors. Such elevator installations comprise an elevator car and, as the case may be, a counterweight. The elevator car and the counterweight can be traversed along the elevator shaft in opposite directions. Both the elevator car and the counterweight are guided on their assigned guide rails. Such a guide rail comprises a plurality of guide-rail segments which are arranged together in a row and, during the installation of the guide rail, are aligned and fixed in turn one after the other in the elevator shaft. For this purpose, positioning gauges are usually inserted and fastened in a shaft pit of the elevator shaft and also in a shaft head of the elevator shaft. Such positioning gauges comprise means in order, for example, to fasten alignment cords thereto. After their installation, such alignment cords are tensioned along the elevator shaft and form an aid for the alignment of guide-rail segments or guide rails.
Following such positioning of the alignment cord, a first guide-rail segment is fixed in the shaft pit and aligned with the aid of the alignment cord in the subsequent course of the installation of the guide rail. The alignment can be carried out such that the first guide-rail segment is spaced apart over its entire length at a fixed alignment distance from the alignment cord, which means that the guide-rail segment is arranged parallel to the alignment cord. Further guide-rail segments are then arranged in a row with the respective previously aligned and fixed guide-rail segment, are aligned with the aid of the alignment cord and fixed. The alignment of the guide-rail segments can be carried out in such a way that the guide-rail segment is arranged as parallel as possible to the alignment cord. This method of installing an individual guide-rail segment is repeated until such time as the guide rail has the required length, i.e. a last one of the guide-rail segments is aligned and fixed in the region of the shaft head or the shaft pit. Throughout the installation of the guide rails, the alignment cord runs rectilinearly tensioned between these aforementioned positioning gauges.
All buildings comprising elevator shafts are subject to movements. Such movements are caused by external influences, for example due to solar radiation and/or wind. The elevator shaft arranged in the building becomes correspondingly deformed in the course of the installation of the individual guide-rail segments. The effect of this is that the installed guide rail does not have the desired straight course. In addition, the use of the method just described means that the guide rail, proceeding from the first-installed guide-rail segment, is not necessarily arranged essentially parallel to the alignment cord. The reason is that the elevator shaft, on account of the external influences, possibly already during the alignment of the second guide-rail segment to be installed, has a different shape than was the case when the first guide-rail segment was installed. Accordingly, the spacing present between the lower portion of the second guide-rail segment and the alignment cord no longer corresponds to the alignment spacing in the case of the alignment of the second guide-rail segment. Even if each individual guide-rail segment has been aligned parallel with the alignment cord, readjustments of the individual guide-rail segments are therefore required with a considerable amount of time being spent.
The problem of the invention, therefore, is to propose a method for installing a guide rail that allows less time to be spent on installing the guide rail.